Gold, a leading export commodity, has undergone a resurgence. After a long period of low production, gold output almost tripled in the late 1990s, from 1,500 kg in 1996 to 4,450 in 1999. In 2001, output was 3,650 kg. Gold and silver mines were in León, Chontales, and Zelaya departments. Mineral production for 2001 included silver, 1,590 kg, down from 4,000 in 1998; marine salt, 28,100 tons, up from 15,132 in 1998; and crude gypsum and anhydrite, 28,100 tons, up from 15,820 in 1997. Bentonite, lime, limestone, sand and gravel, and crushed stone were also produced. Deposits of iron, copper, lead, antimony, and zinc have been uncovered. Mining accounted for 1% of the country's GDP.
In the mid-20th century, Nicaragua ranked roughly 15th in gold production, and the development of gold mining was emphasized during the Sandinista era, when the entire mining industry was nationalized. Gold exports reached $39.9 million in 1980, fell to $15 million in 1982, and were then suspended through 1985. The Corporación Nicaragüense de Minas (INMINE), a subsidiary of the government holding company, controlled most of the country's mineral exploration and production. In 2001, the Congress passed a Mining Code despite opposition from small-scale miners and environmentalists, who argued the law would unduly benefit multinational companies and lead to environmental damage; Congress was investigating ways to protect the interests of small-scale miners, and the new law made submission of environmental impact statements mandatory. In 1997, a ban on new concessions was lifted.